Are my calculations correct for a swimming pool?

I’m looking to put in a geothermal heat pump to heat my parents swimming pool. It’s 40’x20’ and 27,000 gallons. The target water temperature is 85 degrees and I’m basing the average air temperature at 60 degrees assuming they will be using the pool earlier in the year (May-September). The house is in the tri-state New York area. My calculations result in needing 100,000 BTU’s to maintain an 85 degree pool.

If this is a rectangular pool (or not too oddly shaped) the best thing any pool owner could do FIRST is to install an automatic pool cover. A nice cedar-wood bench can be built over the pool cover roller using a microlam beam. Most pool heat loss is by evaporation. With such automatic cover (totally different from a winter type cover), which is only rolled back with a switch when they want to swim, the size you mentioned should be ok, otherwise it seems too low to me for NY. Automatic pool covers also cut chemical costs to almost nil, pool filter pumps don't have to run much, even small children can walk around the pool unsupervised, no leaves in the pool and the terrible humidity damage problems in indoor pool installations are solved.
I am currently planning to install an AquaCal WS05 for a smaller 12x24 outdoor pool, plan to have its source water in series from my 5-ton open-loop geothermal heat pump cooling my Delaware home, but even then plan on the benefits of a motorized cover.
Has anybody integrated the controls for such 2 GT systems in series? My open loop system gets its source water from a Franklin SubDrive 75 variable -speed well pump which also does dual duty for my lawn sprinkler system, outdoor faucetts, etc. Best investment ever made since propane costs in Delaware are very high. COOP Electric is only 12 ct/kw here.